The popularity of gas barbecue grills and related outdoor gas burner devices has increased tremendously over the last twenty-five years. In contrast to charcoal barbecue grills, gas barbecue grills employ a burner assembly that requires a combustible fluid, for example, propane or natural gas, as a fuel source. Barbecue grills with gas burner elements have proven extremely popular with consumers because they provide controlled, uniform heat distribution. In addition, gas burner assemblies are relatively simple to operate, generally require less maintenance and clean-up time, and are suitable for outdoor fireplace devices as well.
There are numerous arrangements and differing structures for burner assemblies used in outdoor devices such as barbecue grills. Often these take the form of elongated burner tubes that are linked together with cross-ignition structures that provide transfer of flame from one row of burner ports to another row of ports. Such cross-ignition structures are sometimes provided as a feature in the are where the burner is ignited by an ignitor at a proximal end of the burner. Other times the cross-ignition feature is provided at the distal or terminal end of the burner. In either arrangement, the cross-ignition structure in conventional burners is located adjacent each row of burner ports, and thereby provides a flame transfer between the two rows. On example of such structure is found in a barbecue grills structure.
An example of a conventual burner assembly having a burner tube arrangement and a cross-ignition structure is found in a portable gas barbecue grill product marketed by the Assignee of the present patent application. That barbecue grill product utilizes a linear burner tube with a first end connected to a fuel source and a second end that is crimped. The burner tube has two distinct rows of burner outlet ports through which fuel exits and flames emanate. Each row of outlet ports is positioned on opposed side walls of the burner tube. At the proximal end of the tube, the bottom wall of the burner tube has an ignition slot that is cooperatively positioned with an ignitor in the firebox. When the ignitor is activated, fuel that has flown through the ignition slot is ignited and the flame is transferred to each of the two rows of outlet ports. Thus, the ignition slot provides cross-ignition of the outlet ports.
Another example of a conventional burner assembly with cross-ignition structure is that of a cast metal linear burner with a set of outlet ports on each of opposed side walls to provide a row of flame on each side of the burner. At one end of the burner, a slot is cut into the end wall to connect the rows of burner ports on each side of the burner. A second slot is also formed in a like manner at the opposite end of the burner. When the burner assembly is installed in the firebox for use, at least one of the slots is located at the ignitor to cross-ignite the rows of burner ports simultaneously. Yet another example of a burner assembly of the prior art construction is U.S. Pat. No. 6,102,029 to Schlosser et al., which is assigned to the Assignee of the present invention. As shown in FIGS. 3-5, the burner assembly 10 generally comprises a first burner tube 21, a second burner tube 22, a third burner 23, and a crossover tube 24. Other types of such burner and cross-ignition arrangements are available as this feature has become more common in the industry.
Conventional gas burner assemblies, including cast burner elements and burner tubes, sometimes may be susceptible to flame disturbances which can be caused by high winds or the sudden dropping of the grill cover onto the firebox. A disturbance to the flame exiting the burner element or tube can negatively affect its performance. For example, when the cover is in an open position, a gust of wind can enter the firebox and cause the flames to “flicker” or diminish. Also, rapid closing of the barbecue grill, such as by slamming the cover closed, can cause fame disturbance and in some structured may cause the flame to be extinguished. One way in which this issue has been addressed is by standard tests being used in the industry in certain counties. For example, one test used in the barbecue grill industry involves repeated dropping of the grill lid from an elevated distance onto the firebox to observe whether the flame of the burner will be disrupted and potentially extinguish. Of course, depending on the specific structure of a particular grill assembly, the possibility of flame disturbance or extinguishing will vary. Some of the more significant variables may include the size of the firebox, depth of the firebox, depth of the burner location, positioning of structure between the cooking grate and the burner, and whether the burner has single or multiple rows of ports.
Therefore, there is a need for a burner tube assembly that with at least one stabilization structure that maintains and stabilizes the flame region to prevent disturbance and/or extinguishment of the flames. Also, there is a need for a burner assembly with a flame stabilization structure wherein the burner assembly is compact and capable of being employed in a wide variety of cooking chambers. The present invention is provided to resolve such a need and enhance versatility in outdoor gas burner structures.